A total of 337 people plan to run in the next House of Councillors election, which is likely to be held in July, and vie for 121 of the chamber's 242 seats, a Kyodo News tally showed Thursday.
Prime Minister Shinzo Abe's Liberal Democratic Party and its coalition partner New Komeito party aim to win a majority in the election to gain control of both houses of parliament. Currently the ruling coalition holds a majority in the more powerful lower chamber, but the upper house is controlled by the opposition bloc.
The six-year term of 121 upper house members will expire on July 28, and the voting will likely be held on July 21, according to rules under the Public Office Election Law.
Major campaign issues will include amendment to the nation's Constitution, Japan's participation in the Trans-Pacific Partnership free trade talks, Abe's economic policies dubbed "Abenomics," reconstruction from the March 2011 disaster and the restart of nuclear plants.
The total number of potential candidates increased by 21 from the figure in a Kyodo News survey conducted three years ago. But the number of candidates to be fielded by political parties decreased by 16.
Of the 121 seats, 73 are to be filled through the country's 47 prefectural constituencies and 48 through the proportional representation system, with voters casting two ballots.
By party, the LDP has picked candidates for all the prefectural constituencies -- a total 49 candidates in all for those seats.
But the major opposition Democratic Party of Japan, which is reeling from the devastating loss it suffered in the House of Representatives election last December, has so far failed to complete its list of candidates for the prefectural districts.
The opposition Japan Restoration Party, co-headed by Osaka Mayor Toru Hashimoto and former Tokyo Gov. Shintaro Ishihara, and Your Party will jointly field candidates in some constituencies.
The upcoming upper house race will be the first national election to allow the use of Facebook, Twitter and other social networking websites in Japan.